Theoretical calculation to create ion source using electrospray in atmosphere

Analysis of water-containing samples has increasing demands especially in on-site investigation. Therefore, we are aiming to develop an imaging mass spectrometry in atmospheric pressure. In this paper, how to make an ion beam in atmosphere is designed and devised based on electrospray ionization (ESI) phenomena. In case of existing “desorption electrospray ionization mass spectrometry (DESI-MS)” using electrospray, specimen is dissolved in sprayed solvent, and they diffuse in it. It is possible to detect sensitively by using the solvents which is soluble in the component as long as the component in the sample is identified prior to the analysis. The condition of wet sample surface by the electrospray may affect spatial resolution of the sample depending on the combination the variety samples and solvents. We considered that the analysis can be possible regardless of the dissolved or undissolved constituents in solvents by causing physical sputtering of the sample surface using electrospray ion beam. In order to realize this sputtering phenomenon in atmosphere, it is necessary to calculate sputtering conditions. This calculation process is halfway stages for this study, and the condition for physical sputtering is mainly calculated in terms of Rayleigh limit.